mineral

Tumbled chalcedony (likely pale agate or quartz)

Chalcedony, microcrystalline SiO₂

AI-generated identification · may be incorrect

Translucent cream-to-pink, waxy/glassy luster, rounded and polished; hardness about 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, specific gravity about 2.6.

Identified September 15, 2026More mineral →

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Physical properties

Translucent cream-to-pink, waxy/glassy luster, rounded and polished; hardness about 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, specific gravity about 2.6.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, precipitating as microcrystalline quartz; individual pieces may range from ancient volcanic-hosted material to younger alluvial deposits.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and lapidary tumbling; attractive banding could indicate agate, while uniform color suggests common chalcedony.

Geological facts

Chalcedony is a quartz variety composed of intergrown microscopic quartz crystals; its translucent appearance and smooth waxy surface are characteristic.

Field identification & locations

Commonly found in volcanic terrains and river gravels worldwide, especially Brazil, Uruguay, Mexico, India, Madagascar, and the western United States. Identify with its hardness, waxy translucence, and resistance to scratching by steel; a definitive distinction from glass requires testing.